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I have a 1987 2.3l Ford Ranger, the gas model, not the turbo diesel. It's been setting for a long time and had some electrical issues which we solved. Turns out the clutch sensor wire through the firewall was faulty. Ran a new one and now it will crank when the key is turned. It didn't seem like we were getting spark so we plugged a spark plug directly into the coil and grounded it. When cranking, we would expect to see the spark plug spark 4 times per revolution. However that isn't anywhere close to what we are seeing. Instead, when we first crank the engine we may get one or two initial sparks, then, no matter how long we crank the engine it will not spark again until after we let off the key and stop cranking, then it will spark one or two more times. We've replaced the ignition switch, the ignition control module, and the distributor. We decided not to replace the coil because when it does spark it is a very strong white/blue flash. Any ideas what would cause this symptom?

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    Do you have 12v on the positive side of the coil while the engine is cranking?
    – HandyHowie
    Feb 12, 2022 at 20:44
  • @handyhowie just checked this. It drops down to 8.7ish v while cranking. Battery maintainer is only able to keep it at 12.87 with ignition off
    – Oxymoron
    Feb 13, 2022 at 22:02
  • @HandyHowie I hooked it up to my 2020 f150 to keep the battery at a comfortable 14.2v the whole time. While cranking confirmed the battery stayed at 14.2v but the positive lead to the coil still drops to 8.5v
    – Oxymoron
    Feb 13, 2022 at 22:11
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    Do you have a wiring diagram for the ignition system for the car you have? If so, can you share it?
    – HandyHowie
    Feb 14, 2022 at 6:51
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    Presumably it was the RED/LIGHT GREEN wire that is the positive side of the HT coil. It should be at battery voltage when turning the engine over according to the wiring diagram. I would investigate why the voltage is dropping. The supply is coming directly from the ignition switch. You could check the voltage at the different places that the RED/LIGHT GREEN wire connects. Can you see that colour wire on the ignition switch? Does the voltage on the yellow wires on the Ignition switch drop below battery voltage?
    – HandyHowie
    Feb 21, 2022 at 17:39

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